Soft and Conditionable Chemical Mechanical Window Polishing Pad

ABSTRACT

A chemical mechanical polishing pad is provided containing: a polishing layer; a plug in place endpoint detection window block; a rigid layer; and, a hot melt adhesive bonding the polishing layer to the rigid layer; wherein the polishing layer comprises the reaction product of ingredients, including: a polyfunctional isocyanate; and, a curative package; wherein the curative package contains an amine initiated polyol curative and a high molecular weight polyol curative; wherein the polishing layer exhibits a density of greater than 0.6 g/cm 3 ; a Shore D hardness of 5 to 40; an elongation to break of 100 to 450%; and, a cut rate of 25 to 150 μm/hr; and, wherein the polishing layer has a polishing surface adapted for polishing the substrate. Also provide are methods of making and using the chemical mechanical polishing pad.

The present invention relates to chemical mechanical polishing pads andmethods of making and using the same. More particularly, the presentinvention relates to a chemical mechanical polishing pad comprising apolishing layer; a plug in place endpoint detection window block; arigid layer; and, a hot melt adhesive bonding the polishing layer to therigid layer; wherein the polishing layer comprises the reaction productof ingredients, including: a polyfunctional isocyanate; and, a curativepackage; wherein the curative package contains an amine initiated polyolcurative and a high molecular weight polyol curative; wherein thepolishing layer exhibits a density of greater than 0.6 g/cm³; a Shore Dhardness of 5 to 40; an elongation to break of 100 to 450%; and, a cutrate of 25 to 150 μm/hr; and, wherein the polishing layer has apolishing surface adapted for polishing the substrate.

In the fabrication of integrated circuits and other electronic devices,multiple layers of conducting, semiconducting and dielectric materialsare deposited onto and removed from a surface of a semiconductor wafer.Thin layers of conducting, semiconducting and dielectric materials maybe deposited using a number of deposition techniques. Common depositiontechniques in modern wafer processing include physical vapor deposition(PVD), also known as sputtering, chemical vapor deposition (CVD),plasma-enhanced chemical vapor deposition (PECVD) and electrochemicalplating, among others. Common removal techniques include wet and dryisotropic and anisotropic etching, among others.

As layers of materials are sequentially deposited and removed, theuppermost surface of the wafer becomes non-planar. Because subsequentsemiconductor processing (e.g., metallization) requires the wafer tohave a flat surface, the wafer needs to be planarized. Planarization isuseful for removing undesired surface topography and surface defects,such as rough surfaces, agglomerated materials, crystal lattice damage,scratches and contaminated layers or materials.

Chemical mechanical planarization, or chemical mechanical polishing(CMP), is a common technique used to planarize or polish work piecessuch as semiconductor wafers. In conventional CMP, a wafer carrier, orpolishing head, is mounted on a carrier assembly. The polishing headholds the wafer and positions the wafer in contact with a polishinglayer of a polishing pad that is mounted on a table or platen within aCMP apparatus. The carrier assembly provides a controllable pressurebetween the wafer and polishing pad. Simultaneously, a polishing medium(e.g., slurry) is dispensed onto the polishing pad and is drawn into thegap between the wafer and polishing layer. To effect polishing, thepolishing pad and wafer typically rotate relative to one another. As thepolishing pad rotates beneath the wafer, the wafer sweeps out atypically annular polishing track, or polishing region, wherein thewafer's surface directly confronts the polishing layer. The wafersurface is polished and made planar by chemical and mechanical action ofthe polishing layer and polishing medium on the surface.

Pad surface “conditioning” or “dressing” is critical to maintain aconsistent polishing surface for stable polishing performance. Over timethe polishing surface of the polishing pad wears down, smoothing overthe microtexture of the polishing surface—a phenomenon called “glazing”.Polishing pad conditioning is typically achieved by abrading thepolishing surface mechanically with a conditioning disk. Theconditioning disk has a rough conditioning surface typically comprisedof embedded diamond points. The conditioning disk is brought intocontact with the polishing surface either during intermittent breaks inthe CMP process when polishing is paused (“ex situ”), or while the CMPprocess is underway (“in situ”). Typically the conditioning disk isrotated in a position that is fixed with respect to the axis of rotationof the polishing pad, and sweeps out an annular conditioning region asthe polishing pad is rotated. The conditioning process as described cutsmicroscopic furrows into the pad surface, both abrading and plowing thepad material and renewing the polishing texture.

Semiconductor devices are becoming increasingly complex with finerfeatures and more metallization layers. This trend requires improvedperformance from polishing consumables in order to maintain planarityand limit polishing defects. The latter can create electrical breaks orshorts of the conducting lines that would render the semiconductordevice non-functional. It is generally known that one approach to reducepolishing defects, such as micro-scratches or chatter marks, is to use asofter polishing pad.

A family of soft polyurethane polishing layers are disclosed by James,et al. in U.S. Pat. No. 7,074,115. James et al. discloses a polishingpad comprising a reaction product of an isocyanate-terminated urethaneprepolymer with an aromatic diamine or polyamine curative, wherein thereaction product exhibits a porosity of at least 0.1 volume percent, aKEL energy loss factor at 40° C. and a 1 rad/sec of 385 to 750 l/Pa, anda modulus E at 40° C. and 1 rad/sec of 100 to 400 MPa.

As described above, it is necessary to diamond condition the surface ofchemical mechanical polishing pads to create a favorable microtexturefor optimum polishing performance. However, it is difficult to createsuch texture in conventional polishing layer materials, such as thosedescribed by James et al., because these materials exhibit a highductility, as measured by tensile elongation to break values. As aresult, when these materials are subjected to conditioning with adiamond conditioning disk, rather than cutting furrows into the pad'ssurface, the diamonds in the conditioning disk simply push the padmaterial aside without cutting. Hence, very little texture is created inthe surface of these conventional materials as a result of conditioningwith a diamond conditioning disk.

Another related problem with these conventional chemical mechanicalpolishing pad materials arises during the machining process to formmacro groove patterns in the pad surface. Conventional chemicalmechanical polishing pads are typically provided with a groove patterncut into their polishing surface to promote slurry flow and to removepolishing debris from the pad-wafer interface. Such grooves arefrequently cut into the polishing surface of the polishing pad eitherusing a lathe or by a CNC milling machine. With soft pad materials,however, a similar problem to that of diamond conditioning occurs, suchthat after the cutting bit has passed, the pad material simply reboundsand the grooves formed close in on themselves. Thus groove quality ispoor and it is more difficult to successfully manufacture commerciallyacceptable pads with such soft materials. This problem worsens as thehardness of the pad material decreases.

Accordingly, there is a continuing need for chemical mechanicalpolishing pads that provide a physical property profile that correlateswell with that associated with low defect formulations, but which alsoimparts enhanced conditionability to the polishing layer (i.e., exhibitsa cut rate of 25 to 150 μm/hr).

The present invention provides a chemical mechanical polishing pad,comprising: a polishing layer having a polishing surface and a basesurface, a counterbore opening, a through opening, an average thickness,T_(P-avg), measured in a direction perpendicular to the polishingsurface from the polishing surface to the base surface; a plug in placeendpoint detection window block having an average thickness, T_(W-avg),along an axis perpendicular to a plane of the polishing surface; a rigidlayer having a top surface and a bottom surface; a hot melt adhesiveinterposed between the base surface of the polishing layer and the topsurface of the rigid layer; wherein the hot melt adhesive bonds thepolishing layer to the rigid layer; optionally, a pressure sensitiveplaten adhesive; wherein the pressure sensitive platen adhesive isdisposed on the bottom surface of the rigid layer; optionally, a releaseliner; wherein the pressure sensitive platen adhesive is interposedbetween the bottom surface of the rigid layer and the optional releaseliner; wherein the polishing layer comprises the reaction product ofingredients, comprising: a polyfunctional isocyanate; and, a curativepackage, comprising: at least 5 wt % of an amine initiated polyolcurative, wherein the amine initiated polyol curative contains at leastone nitrogen atom per molecule; wherein the amine initiated polyolcurative has an average of at least three hydroxyl groups per molecule;25 to 95 wt % of a high molecular weight polyol curative, wherein thehigh molecular weight polyol curative has a number average molecularweight, M_(N), of 2,500 to 100,000; and wherein the high molecularweight polyol curative has an average of 3 to 10 hydroxyl groups permolecule; and, 0 to 70 wt % of a difunctional curative; wherein thepolishing layer exhibits a density of greater than 0.6 g/cm³; a Shore Dhardness of 5 to 40; an elongation to break of 100 to 450%; and, a cutrate of 25 to 150 μm/hr; wherein the through opening extends through thepolishing layer from the polishing surface to the base surface; whereinthe counterbore opening opens on the polishing surface, enlarges thethrough opening and forms a ledge; wherein the counterbore opening hasan average depth, D_(O-avg), from a plane of the polishing surface tothe ledge measured in a direction perpendicular to the plane of thepolishing surface; wherein the average depth, D_(O-avg), is less thanthe average thickness, T_(P-avg); wherein the plug in place endpointdetection window block is disposed within the counterbore opening; and,wherein the plug in place endpoint detection window block is bonded tothe polishing layer.

The present invention provides a chemical mechanical polishing pad,comprising: a polishing layer having a polishing surface and a basesurface, a counterbore opening, a through opening, an average thickness,T_(P-avg), measured in a direction perpendicular to the polishingsurface from the polishing surface to the base surface; a plug in placeendpoint detection window block having an average thickness, T_(W-avg),along an axis perpendicular to a plane of the polishing surface; a rigidlayer having a top surface and a bottom surface; a hot melt adhesiveinterposed between the base surface of the polishing layer and the topsurface of the rigid layer; wherein the hot melt adhesive bonds thepolishing layer to the rigid layer; optionally, a pressure sensitiveplaten adhesive; wherein the pressure sensitive platen adhesive isdisposed on the bottom surface of the rigid layer; optionally, a releaseliner; wherein the pressure sensitive platen adhesive is interposedbetween the bottom surface of the rigid layer and the optional releaseliner; wherein the polishing layer comprises the reaction product ofingredients, comprising: a polyfunctional isocyanate; and, a curativepackage, comprising: at least 5 wt % of an amine initiated polyolcurative, wherein the amine initiated polyol curative contains at leastone nitrogen atom per molecule; wherein the amine initiated polyolcurative has an average of at least three hydroxyl groups per molecule;25 to 95 wt % of a high molecular weight polyol curative, wherein thehigh molecular weight polyol curative has a number average molecularweight, M_(N), of 2,500 to 100,000; and wherein the high molecularweight polyol curative has an average of 3 to 10 hydroxyl groups permolecule; and, 0 to 70 wt % of a difunctional curative; wherein thepolishing layer exhibits a density of greater than 0.6 g/cm³; a Shore Dhardness of 5 to 40; an elongation to break of 100 to 450%; and, a cutrate of 25 to 150 μm/hr; wherein the through opening extends through thepolishing layer from the polishing surface to the base surface; whereinthe counterbore opening opens on the polishing surface, enlarges thethrough opening and forms a ledge; wherein the counterbore opening hasan average depth, D_(O-avg), from a plane of the polishing surface tothe ledge measured in a direction perpendicular to the plane of thepolishing surface; wherein the average depth, D_(O-avg), is less thanthe average thickness, T_(P-avg); wherein the plug in place endpointdetection window block is disposed within the counterbore opening;wherein the plug in place endpoint detection window block is bonded tothe polishing layer; wherein the top surface of the rigid layer isungrooved; wherein the bottom surface of the rigid layer is ungrooved;and, wherein the top surface and the bottom surface of the rigid layerhave a roughness, Ra, of 1 to 500 nm.

The present invention provides a method for manufacturing a chemicalmechanical polishing pad, comprising: providing a polishing layer havinga polishing surface, a base surface and an average thickness, T_(P-avg),measured in a direction perpendicular to the polishing surface from thepolishing surface to the base surface; providing a plug in placeendpoint detection window block having an average thickness, T_(W-avg),along an axis perpendicular to a plane of the polishing surface;providing a rigid layer having a top surface and a bottom surface;providing a hot melt adhesive in an uncured state; providing a throughopening that extends through the polishing layer from the polishingsurface to the base surface; providing a counterbore opening that openson the polishing surface, enlarges the through opening and forms aledge; wherein the counterbore opening has an average depth, D_(O-avg),from a plane of the polishing surface to the ledge measured in adirection perpendicular to the polishing surface; wherein the averagedepth, D_(O-avg), is less than the average thickness, T_(P-avg);interposing the hot melt adhesive in its uncured state between the basesurface of the polishing layer and the top surface of the rigid layer;curing the hot melt adhesive, bonding the polishing layer and the rigidlayer together; and, disposing the plug in place endpoint detectionwindow block within the counterbore opening and bonding the plug inplace endpoint detection window block to the polishing layer; whereinthe polishing layer comprises the reaction product of ingredients,comprising: a polyfunctional isocyanate; and, a curative package,comprising: at least 5 wt % of an amine initiated polyol curative,wherein the amine initiated polyol curative contains at least onenitrogen atom per molecule; wherein the amine initiated polyol curativehas an average of at least three hydroxyl groups per molecule; 25 to 95wt % of a high molecular weight polyol curative, wherein the highmolecular weight polyol curative has a number average molecular weight,M_(N), of 2,500 to 100,000; and wherein the high molecular weight polyolcurative has an average of 3 to 10 hydroxyl groups per molecule; and, 0to 70 wt % of a difunctional curative; wherein the polishing layerexhibits a density of greater than 0.6 g/cm³; a Shore D hardness of 5 to40; an elongation to break of 100 to 450%; and, a cut rate of 25 to 150μm/hr.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a depiction of a perspective view of a chemical mechanicalpolishing pad of the present invention.

FIG. 2 is a depiction of a cross sectional cut away view of a chemicalmechanical polishing pad of the present invention.

FIG. 3 is a top plan view of a chemical mechanical polishing pad of thepresent invention.

FIG. 4 is a side perspective view of a polishing layer of the presentinvention.

FIG. 5 is a side elevational view of a cross section of a chemicalmechanical polishing pad of the present invention.

FIG. 6 is a side elevational view of a plug in place endpoint detectionwindow block of the present invention.

FIG. 7 is a depiction of a cross sectional cut away view of a chemicalmechanical polishing pad of the present invention.

DETAILED DESCRIPTION

The term “average total thickness, T_(T-avg)” as used herein and in theappended claims in reference to a chemical mechanical polishing pad (10)having a polishing surface (14) means the average thickness, T_(T), ofthe chemical mechanical polishing pad measured in a direction normal tothe polishing surface (14). (See FIGS. 1, 2, 5 and 7).

The term “substantially circular cross section” as used herein and inthe appended claims in reference to a chemical mechanical polishing pad(10) means that the longest radius, r, of the cross section from thecentral axis (12) to the outer perimeter (15) of the polishing surface(14) of the polishing layer (20) is ≦20% longer than the shortestradius, r, of the cross section from the central axis (12) to the outerperimeter (15) of the polishing surface (14). (See FIG. 1).

The chemical mechanical polishing pad (10) of the present invention ispreferably adapted for rotation about a central axis (12). (See FIG. 1).Preferably, the polishing surface (14) of polishing layer (20) is in aplane (28) perpendicular to the central axis (12). The multilayerchemical mechanical polishing pad (10) is optionally adapted forrotation in a plane (28) that is at an angle, γ, of 85 to 95° to thecentral axis (12), preferably, of 90° to the central axis (12).Preferably, the polishing layer (20) has a polishing surface (14) thathas a substantially circular cross section perpendicular to the centralaxis (12). Preferably, the radius, r, of the cross section of thepolishing surface (14) perpendicular to the central axis (12) varies by≦20% for the cross section, more preferably by ≦10% for the crosssection.

The chemical mechanical polishing pad (10) of the present invention isspecifically designed to facilitate the polishing of a substrateselected from at least one of a magnetic substrate, an optical substrateand a semiconductor substrate.

The chemical mechanical polishing pad (10) has a polishing layer (20)that exhibits a unique combination of low hardness (i.e., Shore D≦40) toprovide low defect polishing performance and a low tensile elongation(i.e., elongation to break≦450%) which provides both machinability tofacilitate the formation of grooves in the polishing layer andconditionability to facilitate the formation of microtexture using adiamond conditioning disk. In addition, the balance of propertiesenabled by the polishing layer of the present invention provides theability to, for example, polish semiconductor wafers without damagingthe wafer surface by creating micro-scratch defects that couldcompromise the electrical integrity of the semiconductor device.

The chemical mechanical polishing pad (10) of the present invention,comprises (preferably, consists of): a polishing layer (20) having apolishing surface (14), a base surface (17), a counterbore opening (40),a through opening (35), an average thickness, T_(P-avg), measured in adirection perpendicular to the polishing surface (14) from the polishingsurface (14) to the base surface (17); a plug in place endpointdetection window block (30) having an average thickness, T_(W-avg),along an axis perpendicular to a plane of the polishing surface (A); arigid layer (25) having a top surface (26) and a bottom surface (27); ahot melt adhesive (23) interposed between the base surface (17) of thepolishing layer (20) and the top surface (26) of the rigid layer (25);wherein the hot melt adhesive (23) bonds the polishing layer (20) to therigid layer (25); optionally, a pressure sensitive platen adhesive (70);wherein the pressure sensitive platen adhesive (70) is disposed on thebottom surface (27) of the rigid layer (25) (preferably, wherein theoptional pressure sensitive platen adhesive facilitates mounting of thechemical mechanical polishing pad on a polishing machine); optionally, arelease liner (75); wherein the pressure sensitive platen adhesive (70)is interposed between the bottom surface (27) of the rigid layer (25)and the optional release liner (75); wherein the polishing layer (20)comprises the reaction product of ingredients, comprising: apolyfunctional isocyanate; and, a curative package, comprising: at least5 wt % (preferably 5 to 30 wt %; more preferably 5 to 25 wt %; mostpreferably 5 to 20 wt %) of an amine initiated polyol curative, whereinthe amine initiated polyol curative contains at least one nitrogen atomper molecule (preferably, wherein the amine initiated polyol curativecontains one to four nitrogen atoms per molecule; more preferably,wherein the amine initiated polyol curative contains two to fournitrogen atoms per molecule; most preferably, wherein the amineinitiated polyol curative contains two nitrogen atoms per molecule);wherein the amine initiated polyol curative has an average of at leastthree hydroxyl groups (preferably 3 to 6 hydroxyl groups; morepreferably 3 to 5 hydroxyl groups; most preferably 4 hydroxyl groups)per molecule; (preferably wherein the amine initiated polyol curativehas a number average molecular weight of ≦700; more preferably 150 to650; still more preferably 200 to 500; most preferably 250 to 300); 25to 95 wt % (preferably 35 to 90 wt %; more preferably 50 to 75 wt %;most preferably 60 to 75 wt %) of a high molecular weight polyolcurative, wherein the high molecular weight polyol curative has a numberaverage molecular weight, M_(N), of 2,500 to 100,000 (preferably 5,000to 50,000; more preferably 7,500 to 25,000; most preferably 10,000 to12,000); and wherein the high molecular weight polyol curative has anaverage of 3 to 10 hydroxyl groups (preferably 4 to 8 hydroxyl groups;more preferably 5 to 7; most preferably 6) per molecule; and, 0 to 70 wt% (preferably 5 to 60 wt %; more preferably 10 to 50 wt %; still morepreferably 10 to 30 wt %; most preferably 10 to 20 wt %) of adifunctional curative; wherein the polishing layer exhibits a density of≧0.6 g/cm³ (preferably, 0.6 to 1.2 g/cm³; more preferably 0.7 to 1.1g/cm³; most preferably 0.75 to 1.0 g/cm³); a Shore D hardness of 5 to 40(preferably 5 to 30; more preferably 5 to 20; most preferably 5 to 15);an elongation to break of 100 to 450% (preferably 125 to 425%; morepreferably 150 to 300%; most preferably 150 to 200%); and, a cut rate of25 to 150 μm/hr (preferably 30 to 125 μm/hr; more preferably 30 to 100μm/hr; most preferably 30 to 60 μm/hr); wherein the through opening (35)extends through the polishing layer (20) from the polishing surface (14)to the base surface (17); (preferably, wherein the through opening (35)extends through the chemical mechanical polishing pad from the polishingsurface (14) of the polishing layer (20) to the bottom surface (27) ofthe rigid layer (25); more preferably, wherein the through opening (35)extends through the total thickness, T_(T), of the chemical mechanicalpolishing pad (10)); wherein the counterbore opening (40) opens on thepolishing surface (14), enlarges the through opening (35) and forms aledge (45); wherein the counterbore opening (40) has an average depth,D_(O-avg), from a plane of the polishing surface (28) to the ledge (45)measured in a direction perpendicular to the plane of the polishingsurface (28); wherein the average depth, D_(O-avg), is less than theaverage thickness, T_(P-avg); wherein the plug in place endpointdetection window block (30) is disposed within the counterbore opening(40); and, wherein the plug in place endpoint detection window block(30) is bonded to the polishing layer (20). (See FIGS. 1-7).

Preferably, the polyfunctional isocyanate used in the formation of thepolishing layer (20) contains two reactive isocyanate groups (i.e.,NCO).

Preferably, the polyfunctional isocyanate used in the formation of thepolishing layer (20) is selected from the group consisting of analiphatic polyfunctional isocyanate, an aromatic polyfunctionalisocyanate and a mixture thereof. More preferably, the polyfunctionalisocyanate used in the formation of the polishing layer (20) is adiisocyanate selected from the group consisting of 2,4-toluenediisocyanate; 2,6-toluene diisocyanate; 4,4′-diphenylmethanediisocyanate; naphthalene-1,5-diisocyanate; tolidine diisocyanate;para-phenylene diisocyanate; xylylene diisocyanate; isophoronediisocyanate; hexamethylene diisocyanate; 4,4′-dicyclohexylmethanediisocyanate; cyclohexanediisocyanate; and, mixtures thereof. Still morepreferably, the polyfunctional isocyanate used in the formation of thepolishing layer (20) is an isocyanate terminated urethane prepolymerformed by the reaction of a diisocyanate with a prepolymer polyol.

Preferably, the isocyanate-terminated urethane prepolymer used in theformation of the polishing layer (20) has 2 to 12 wt % unreactedisocyanate (NCO) groups. More preferably, the isocyanate-terminatedurethane prepolymer used in the formation of the polishing layer (20)has 2 to 10 wt % (still more preferably 4 to 8 wt %; most preferably 5to 7 wt %) unreacted isocyanate (NCO) groups.

Preferably the prepolymer polyol used to form the polyfunctionalisocyanate terminated urethane prepolymer is selected from the groupconsisting of diols, polyols, polyol diols, copolymers thereof andmixtures thereof. More preferably, the prepolymer polyol is selectedfrom the group consisting of polyether polyols (e.g.,poly(oxytetramethylene)glycol, poly(oxypropylene)glycol and mixturesthereof); polycarbonate polyols; polyester polyols; polycaprolactonepolyols; mixtures thereof; and, mixtures thereof with one or more lowmolecular weight polyols selected from the group consisting of ethyleneglycol; 1,2-propylene glycol; 1,3-propylene glycol; 1,2-butanediol;1,3-butanediol; 2-methyl-1,3-propanediol; 1,4-butanediol; neopentylglycol; 1,5-pentanediol; 3-methyl-1,5-pentanediol; 1,6-hexanediol;diethylene glycol; dipropylene glycol; and, tripropylene glycol. Stillmore preferably, the prepolymer polyol is selected from the groupconsisting of polytetramethylene ether glycol (PTMEG); ester basedpolyols (such as ethylene adipates, butylene adipates); polypropyleneether glycols (PPG); polycaprolactone polyols; copolymers thereof; and,mixtures thereof. Most preferably, the prepolymer polyol is selectedfrom the group consisting of PTMEG and PPG.

Preferably, when the prepolymer polyol is PTMEG, the isocyanateterminated urethane prepolymer has an unreacted isocyanate (NCO)concentration of 2 to 10 wt % (more preferably of 4 to 8 wt %; mostpreferably 6 to 7 wt %). Examples of commercially available PTMEG basedisocyanate terminated urethane prepolymers include Imuthane® prepolymers(available from COIM USA, Inc., such as, PET-80A, PET-85A, PET-90A,PET-93A, PET-95A, PET-60D, PET-70D, PET-75D); Adiprene® prepolymers(available from Chemtura, such as, LF 800A, LF 900A, LF 910A, LF 930A,LF 931A, LF 939A, LF 950A, LF 952A, LF 600D, LF 601D, LF 650D, LF 667,LF 700D, LF750D, LF751D, LF752D, LF753D and L325); Andur® prepolymers(available from Anderson Development Company, such as, 70APLF, 80APLF,85APLF, 90APLF, 95APLF, 60DPLF, 70APLF, 75APLF).

Preferably, when the prepolymer polyol is PPG, the isocyanate terminatedurethane prepolymer has an unreacted isocyanate (NCO) concentration of 3to 9 wt % (more preferably 4 to 8 wt %, most preferably 5 to 6 wt %).Examples of commercially available PPG based isocyanate terminatedurethane prepolymers include Imuthane® prepolymers (available from COIMUSA, Inc., such as, PPT-80A, PPT-90A, PPT-95A, PPT-65D, PPT-75D);Adiprene® prepolymers (available from Chemtura, such as, LFG 963A, LFG964A, LFG 740D); and, Andur® prepolymers (available from AndersonDevelopment Company, such as, 8000APLF, 9500APLF, 6500DPLF, 7501DPLF).

Preferably, the isocyanate terminated urethane prepolymer used in theformation of the polishing layer (20) is a low free isocyanateterminated urethane prepolymer having less than 0.1 wt % free toluenediisocyanate (TDI) monomer content.

Non-TDI based isocyanate terminated urethane prepolymers can also beused. For example, isocyanate terminated urethane prepolymers includethose formed by the reaction of 4,4′-diphenylmethane diisocyanate (MDI)and polyols such as polytetramethylene glycol (PTMEG) with optionaldiols such as 1,4-butanediol (BDO) are acceptable. When such isocyanateterminated urethane prepolymers are used, the unreacted isocyanate (NCO)concentration is preferably 4 to 10 wt % (more preferably 4 to 8 wt %,most preferably 5 to 7 wt %). Examples of commercially availableisocyanate terminated urethane prepolymers in this category includeImuthane® prepolymers (available from COIM USA, Inc. such as 27-85A,27-90A, 27-95A); Andur® prepolymers (available from Anderson DevelopmentCompany, such as, IE75AP, IE80AP, IE 85AP, IE90AP, IE95AP, IE98AP); and,Vibrathane® prepolymers (available from Chemtura, such as, B625, B635,B821).

Preferably, the curative package used in the formation of the polishinglayer (20) contains: at least 5 wt % (preferably 5 to 30 wt %; morepreferably 5 to 25 wt %; most preferably 5 to 20 wt %) of an amineinitiated polyol curative; 25 to 95 wt % (preferably 35 to 90 wt %; morepreferably 50 to 75 wt %; most preferably 60 to 75 wt %) of a highmolecular weight polyol curative; and, 0 to 70 wt % (preferably 5 to 60wt %; more preferably 10 to 15 wt %; still more preferably 10 to 30 wt%; most preferably 10 to 20 wt %) of a difunctional curative.

Preferably, the amine initiated polyol curative used in the formation ofthe polishing layer (20) contains at least one nitrogen atom permolecule. More preferably, the amine initiated polyol curative usedcontains one to four (still more preferably two to four; most preferablytwo) nitrogen atoms per molecule.

Preferably, the amine initiated polyol curative used in the formation ofthe polishing layer (20) has an average of at least three hydroxylgroups per molecule. More preferably, the amine initiated polyolcurative used has an average of three to six (still more preferablythree to five; most preferably four) hydroxyl groups per molecule.

Preferably, the amine initiated polyol curative used in the formation ofthe polishing layer (20) has a number average molecular weight, M_(N),of ≦700. More preferably, the amine initiated polyol curative used has anumber average molecular weight, M_(N), of 150 to 650 (still morepreferably 200 to 500; most preferably 250 to 300).

Preferably, the amine initiated polyol curative used in the formation ofthe polishing layer (20) has a hydroxyl number (as determined by ASTMTest Method D4274-11) of 350 to 1,200 mg KOH/g. More preferably, theamine initiated polyol curative used has a hydroxyl number of 400 to1,000 mg KOH/g (most preferably 600 to 850 mg KOH/g).

Examples of commercially available amine initiated polyol curativesinclude the Voranol® family of amine initiated polyols (available fromThe Dow Chemical Company); the Quadrol® Specialty Polyols(N,N,N′,N′-tetrakis(2-hydroxypropyl ethylene diamine))(available fromBASF); Pluracol® amine based polyols (available from BASF); Multranol®amine based polyols (available from Bayer MaterialScience LLC);triisopropanolamine (TIPA) (available from The Dow Chemical Company);and, triethanolamine (TEA) (available from Mallinckrodt Baker Inc.). Anumber of preferred amine initiated polyol curatives are listed in TABLE1.

TABLE 1 Number of Hydroxyl Amine initiated polyol OH groups Numbercurative per molecule M_(N) (mg KOH/g) Triethanolamine 3 149 1130Triisopropanolamine 3 192 877 MULTRANOL ® 9138 Polyol 3 240 700MULTRANOL ® 9170 Polyol 3 481 350 VORANOL ® 391 Polyol 4 568 391VORANOL ® 640 Polyol 4 352 638 VORANOL ® 800 Polyol 4 280 801 QUADROL ®Polyol 4 292 770 MULTRANOL ® 4050 Polyol 4 356 630 MULTRANOL ® 4063Polyol 4 488 460 MULTRANOL ® 8114 Polyol 4 568 395 MULTRANOL ® 8120Polyol 4 623 360 MULTRANOL ® 9181 Polyol 4 291 770 VORANOL ® 202 Polyol5 590 475

Without wishing to be bound by theory, in addition to promoting thedesired balance of physical properties in the polishing layer (20)produced therewith, it is believed that the concentration of the amineinitiated polyol curative used in the curative package also acts toautocatalyze its reaction and the reaction of any difunctional curativein the curative package with the unreacted isocyanate (NCO) groupspresent in the polyfunctional diisocyante.

Preferably, the high molecular weight polyol curative used in theformation of the polishing layer (20) has a number average molecularweight, M_(N), of 2,500 to 100,000. More preferably, the high molecularweight polyol curative used has a number average molecular weight,M_(N), of 5,000 to 50,000 (still more preferably 7,500 to 25,000; mostpreferably 10,000 to 12,000).

Preferably, the high molecular weight polyol curative used in theformation of the polishing layer (20) has an average of three to tenhydroxyl groups per molecule. More preferably, the high molecular weightpolyol curative used has an average of four to eight (still morepreferably five to seven; most preferably six) hydroxyl groups permolecule.

Preferably, the high molecular weight polyol curative used in theformation of the polishing layer (20) has a molecular weight that ishigher than the molecular weight of the amine initiated polyol curativeused in the curative package; and, has a hydroxyl number that is lowerthan that of the amine initiated curative used in the curative package.

Examples of commercially available high molecular weight polyolcuratives include Specflex® polyols, Voranol® polyols and Voralux®polyols (available from The Dow Chemical Company); Multranol® SpecialtyPolyols and Ultracel® Flexible Polyols (available from BayerMaterialScience LLC); and Pluracol® Polyols (available from BASF). Anumber of preferred high molecular weight polyol curatives are listed inTABLE 2.

TABLE 2 Number of Hydroxyl High molecular weight OH groups Number polyolcurative per molecule M_(N) (mg KOH/g) Multranol ® 3901 Polyol 3.0 6,00028 Pluracol ® 1385 Polyol 3.0 3,200 50 Pluracol ® 380 Polyol 3.0 6,50025 Pluracol ® 1123 Polyol 3.0 7,000 24 ULTRACEL ® 3000 Polyol 4.0 7,50030 SPECFLEX ® NC630 Polyol 4.2 7,602 31 SPECFLEX ® NC632 Polyol 4.78,225 32 VORALUX ® HF 505 Polyol 6.0 11,400 30 MULTRANOL ® 9185 Polyol6.0 3,366 100 VORANOL ® 4053 Polyol 6.9 12,420 31

Preferably, the difunctional curative used in the formation of thepolishing layer (20) is selected from diols and diamines. Morepreferably, the difunctional curative used is a diamine selected fromthe group consisting of primary amines and secondary amines. Still morepreferably, the difunctional curative used is selected from the groupconsisting of diethyltoluenediamine (DETDA);3,5-dimethylthio-2,4-toluenediamine and isomers thereof;3,5-diethyltoluene-2,4-diamine and isomers thereof (e.g.,3,5-diethyltoluene-2,6-diamine);4,4′-bis-(sec-butylamino)-diphenylmethane;1,4-bis-(sec-butylamino)-benzene; 4,4′-methylene-bis-(2-chloroaniline);4,4′-methylene-bis-(3-chloro-2,6-diethylaniline) (MCDEA);polytetramethyleneoxide-di-p-aminobenzoate; N,N′-dialkyldiamino diphenylmethane; p,p′-methylene dianiline (MDA); m-phenylenediamine (MPDA);4,4′-methylene-bis-(2-chloroaniline) (MBOCA);4,4′-methylene-bis-(2,6-diethylaniline) (MDEA);4,4′-methylene-bis-(2,3-dichloroaniline) (MDCA);4,4′-diamino-3,3′-diethyl-5,5′-dimethyl diphenylmethane,2,2′,3,3′-tetrachloro diamino diphenylmethane; trimethylene glycoldi-p-aminobenzoate; and mixtures thereof. Most preferably, the diaminecuring agent used is selected from the group consisting of4,4′-methylene-bis-(2-chloroaniline) (MBOCA);4,4′-methylene-bis-(3-chloro-2,6-diethylaniline) (MCDEA); and, isomersthereof.

Preferably, the stoichiometric ratio of the reactive hydrogen groups(i.e., the sum of the amine (NH₂) groups and the hydroxyl (OH) groups)in the components of the curative package to the unreacted isocyanate(NCO) groups in the polyfunctional isocyanate is 0.85 to 1.15 (morepreferably 0.90 to 1.10; most preferably 0.95 to 1.05).

The polishing layer (20) optionally further comprises a plurality ofmicroelements. Preferably, the plurality of microelements are uniformlydispersed throughout the polishing layer (20). Preferably, the pluralityof microelements is selected from entrapped gas bubbles, hollow corepolymeric materials, liquid filled hollow core polymeric materials,water soluble materials and an insoluble phase material (e.g., mineraloil). More preferably, the plurality of microelements is selected fromentrapped gas bubbles and hollow core polymeric materials uniformlydistributed throughout the polishing layer (20). Preferably, theplurality of microelements has a weight average diameter of less than150 μm (more preferably of less than 50 μm; most preferably of 10 to 50μm). Preferably, the plurality of microelements comprise polymericmicroballoons with shell walls of either polyacrylonitrile or apolyacrylonitrile copolymer (e.g., Expancel® from Akzo Nobel).Preferably, the plurality of microelements are incorporated into thepolishing layer (20) at 0 to 35 vol % porosity (more preferably 10 to 25vol % porosity).

The polishing layer (20) can be provided in both porous and nonporous(i.e., unfilled) configurations. Preferably, the polishing layer (20)exhibits a density of ≧0.6 g/cm³ as measured according to ASTM D1622.More preferably, the polishing layer (20) exhibits a density of 0.6 to1.2 g/cm³ (still more preferably 0.7 to 1.1 g/cm³; most preferably 0.75to 1.0 g/cm³) as measured according to ASTM D1622.

Preferably, the polishing layer (20) exhibits a Shore D hardness of 5 to40 as measured according to ASTM D2240. More preferably, the polishinglayer (20) exhibits a Shore D hardness of 5 to 30 (still more preferably5 to 20; most preferably 5 to 15) as measured according to ASTM D2240.

Polishing layers exhibiting a Shore D hardness of less than 40 typicallyhave very high elongation to break values (i.e., >600%). Materialsexhibiting such high elongation to break values reversibly deform whensubjected to machining operations, which results in groove formationthat is unacceptably poor and texture creation during diamondconditioning that is insufficient. The unique curative package used inthe formation of the polishing layer (20) of the chemical mechanicalpolishing pad (10) of the present invention provides a low hardnesscoupled with an elongation to break of 100 to 450% as measured accordingto ASTM D412. Preferably, the polishing layer (20) exhibits anelongation to break of 125 to 425% (still more preferably 150 to 300%;most preferably 150 to 200%) as measured according to ASTM D412.

Preferably, the polishing layer (20) exhibits a cut rate of 25 to 150μm/hr as measured using the method described herein in the Examples.More preferably, the polishing layer (20) exhibits a cut rate of 30 to125 μm/hr (still more preferably 30 to 100 μm/hr; most preferably 30 to60 μm/hr) as measured using the method described herein in the Examples.

One of ordinary skill in the art will understand to select a polishinglayer (20) having a thickness, T_(P), suitable for use in a chemicalmechanical polishing pad (10) for a given polishing operation.Preferably, the polishing layer (20) exhibits an average thickness,T_(P-avg), along an axis (A) perpendicular to a plane (28) of thepolishing surface (25). More preferably, the average thickness,T_(P-avg), is 20 to 150 mils (more preferably 30 to 125 mils; mostpreferably 40 to 120 mils). (See FIGS. 2, 5 and 7).

Preferably, the polishing surface (14) of the polishing layer (20) isadapted for polishing a substrate selected from at least one of amagnetic substrate, an optical substrate and a semiconductor substrate(more preferably, a semiconductor substrate; most preferably, asemiconductor wafer). The polishing surface (14) of the polishing layer(20) exhibits at least one of macrotexture and microtexture tofacilitate polishing the substrate. Preferably, the polishing surface(14) exhibits macrotexture, wherein the macrotexture is designed to doat least one of (i) alleviate at least one of hydroplaning; (ii)influence polishing medium flow; (iii) modify the stiffness of thepolishing layer; (iv) reduce edge effects; and, (v) facilitate thetransfer of polishing debris away from the area between the polishingsurface (14) and the substrate being polished.

The polishing surface (14) preferably exhibits macrotexture selectedfrom at least one of perforations and grooves. Preferably, theperforations can extend from the polishing surface (14) part way or allof the way through the thickness of the polishing layer (20).Preferably, the grooves are arranged on the polishing surface (14) suchthat upon rotation of the pad (10) during polishing, at least one groovesweeps over the substrate. Preferably, the grooves are selected fromcurved grooves, linear grooves and combinations thereof. The groovesexhibit a depth of ≧10 mils (preferably, 10 to 150 mils). Preferably,the grooves form a groove pattern that comprises at least two grooveshaving a combination of a depth selected from ≧10 mils, ≧15 mils and 15to 150 mils; a width selected from ≧10 mils and 10 to 100 mils; and apitch selected from ≧30 mils, ≧50 mils, 50 to 200 mils, 70 to 200 mils,and 90 to 200 mils.

Preferably, the polishing layer (20) contains <1 ppm abrasive particlesincorporated therein.

The plug in place endpoint detection window block (30) has a thickness,T_(W), along an axis perpendicular to a plane (28) of the polishingsurface (14). Preferably, the plug in place endpoint detection windowblock (30) has an average thickness, T_(W-avg), along an axis (B)perpendicular to the plane (28) of the polishing surface (25). (See FIG.6). More preferably, the average thickness, T_(W-avg), is 5 to 75 mils(still more preferably 10 to 60 mils; yet still more preferably 15 to 50mils; most preferably, 20 to 40 mils).

One of ordinary skill in the art will know to select a plug in placeendpoint detection window block (30) having a composition appropriate tofacilitate endpoint detection in the intended polishing operation.

The polishing layer (20) has a counterbore opening (40) that enlarges athrough passage (35) that extends through the thickness, T_(P), of thepolishing layer (20), wherein the counterbore opening (40) opens on thepolishing surface and forms a ledge (45) at an interface between thecounterbore opening (40) and the through passage (35) at a depth, D_(O),along an axis, B, parallel with an axis, A, and perpendicular to theplane (28) of the polishing surface (25). (See FIGS. 2, 4-5 and 7).Preferably, the ledge (45) is parallel with the polishing surface (25).Preferably, the ledge (45) is parallel with the polishing surface (25).Preferably, the counterbore opening defines a cylindrical volume with anaxis that is parallel to axis (A). Preferably, the counterbore openingdefines a non-cylindrical volume. Preferably, the plug in place endpointdetection window block (30) is disposed within the counterbore opening(40). Preferably, the plug in place endpoint detection window block (30)is disposed within the counterbore opening (40) and adhered to thepolishing layer (20). Preferably, the plug in place endpoint detectionwindow block (30) is adhered to the polishing layer (20) using at leastone of ultrasonic welding and an adhesive. Preferably, the average depthof the counterbore opening, D_(O-avg), along an axis, B, parallel withan axis, A, and perpendicular to the plane (28) of the polishing surface(25) is 5 to 75 mils (preferably 10 to 60 mils; more preferably 15 to 50mils; most preferably, 20 to 40 mils). Preferably, the average depth ofthe counterbore opening, D_(O-avg), is ≦the average thickness,T_(W-avg), of the plug in place endpoint detection window block (30).(See FIG. 6). More preferably, the average depth of the counterboreopening, D_(O-avg), satisfies the following expression

0.90*T _(W-avg) ≦D _(O-avg) ≦T _(W-avg).

More preferably, the average depth of the counterbore opening,D_(O-avg), satisfies the following expression

0.95*T _(W-avg) ≦D _(O-avg) <T _(W-avg).

Preferably, the rigid layer (25) is made of a material selected from thegroup consisting of a polymer, a metal, a reinforced polymer andcombinations thereof. More preferably, the rigid layer (25) is made of apolymer. Most preferably, the rigid layer (25) is made of a polymerselected from the group consisting of a polyester, a nylon, an epoxy, afiberglass reinforced epoxy; and, a polycarbonate (more preferably, apolyester; still more preferably, a polyethylene terephthalatepolyester; most preferably, a biaxially oriented polyethyleneterephthalate polyester).

Preferably, the rigid layer (25) has an average thickness of >5 to 60mils (more preferably, 6 to 30 mils; still more preferably, 6 to 15mils; most preferably, 6 to 10 mils).

Preferably, the top surface (26) and the bottom surface (27) of therigid layer (25) are both ungrooved. More preferably, the top surface(26) and the bottom surface (27) are both smooth. Most preferably, thetop surface (26) and the bottom surface (27) have a roughness, Ra, of 1to 500 nm (preferably, 1 to 100 nm; more preferably, 10 to 50 nm; mostpreferably 20 to 40 nm) as determined using an optical profilometer.

Preferably, the rigid layer (25) exhibits a Young's Modulus, measuredaccording to ASTM D882-12, of ≧100 MPa (more preferably, 1,000 to 10,000MPa; still more preferably, 2,500 to 7,500 MPa; most preferably, 3,000to 7,000 MPa).

Preferably, the rigid layer (25) exhibits a void fraction of <0.1 vol %(more preferably, <0.01 vol %).

Preferably, the rigid layer (25) is made of a biaxially orientedpolyethylene terephthalate having an average thickness of >5 to 60 mils(preferably, 6 to 30 mils; more preferably, 6 to 15 mils; mostpreferably, 6 to 10 mils); and, a Young's Modulus, measured according toASTM D882-12, of ≧100 MPa (preferably, 1,000 to 10,000 MPa; morepreferably, 2,500 to 7,500 MPa; most preferably, 3,000 to 7,000 MPa).

One of ordinary skill in the art will know how to select an appropriatehot melt adhesive (23) for use in the chemical mechanical polishing pad(10). Preferably, the hot melt adhesive (23) is a cured reactive hotmelt adhesive. More preferably, the hot melt adhesive (23) is a curedreactive hot melt adhesive that exhibits a melting temperature in itsuncured state of 50 to 150° C., preferably of 115 to 135° C. andexhibits a pot life of ≦90 minutes after melting. Most preferably, thehot melt adhesive (23) in its uncured state comprises a polyurethaneresin (e.g., Mor-Melt™ R5003 available from Rohm and Haas).

The chemical mechanical polishing pad (10) is preferably adapted to beinterfaced with a platen of a polishing machine. Preferably, thechemical mechanical polishing pad (10) is adapted to be affixed to theplaten of a polishing machine. The chemical mechanical polishing pad(10) can be affixed to the platen using at least one of a pressuresensitive adhesive and vacuum.

Preferably, the chemical mechanical polishing pad (10) includes apressure sensitive platen adhesive (70) applied to the bottom surface(27) of the rigid layer (25). One of ordinary skill in the art will knowhow to select an appropriate pressure sensitive adhesive for use as thepressure sensitive platen adhesive (70). Preferably, the chemicalmechanical polishing pad (10) will also include a release liner (75)applied over the pressure sensitive platen adhesive (70), wherein thepressure sensitive platen adhesive (70) is interposed between the bottomsurface (27) of the rigid layer (25) and the release liner (75). (SeeFIGS. 2 and 7).

Preferably, the method for manufacturing a chemical mechanical polishingpad (10) of the present invention, comprises: providing a polishinglayer (20) having a polishing surface (14), a base surface (17) and anaverage thickness, T_(P-avg), measured in a direction perpendicular tothe polishing surface (14) from the polishing surface (14) to the basesurface (17); providing a plug in place endpoint detection window block(30) having an average thickness, T_(W-avg), along an axis perpendicularto a plane (28) of the polishing surface (14); providing a rigid layer(25) having a top surface (26) and a bottom surface (27); providing ahot melt adhesive (23) in an uncured state; providing a through opening(35) that extends through the polishing layer (20) from the polishingsurface (14) to the base surface (17); (preferably, wherein the throughopening (35) extends through the chemical mechanical polishing pad (10)from the polishing surface (14) to the bottom surface (27) of the rigidlayer (25); more preferably, wherein the through opening (35) extendsthrough the total thickness, T_(T), of the chemical mechanical polishingpad (10)); providing a counterbore opening (40) that opens on thepolishing surface (14), enlarges the through opening (35) and forms aledge (45); wherein the counterbore opening (40) has an average depth,D_(O-avg), from a plane (28) of the polishing surface (14) to the ledge(45) measured in a direction perpendicular to the polishing surface(14); wherein the average depth, D_(O-avg), is less than the averagethickness, T_(P-avg); interposing the hot melt adhesive (23) in itsuncured state between the base surface (17) of the polishing layer (20)and the top surface (26) of the rigid layer (25); curing the hot meltadhesive (23), bonding the polishing layer (20) and the rigid layer (25)together; and, disposing the plug in place endpoint detection windowblock (30) within the counterbore opening (40) and bonding the plug inplace endpoint detection window block (30) to the polishing layer (20);wherein the polishing layer (20) comprises the reaction product ofingredients, comprising: a polyfunctional isocyanate; and, a curativepackage, comprising: at least 5 wt % of an amine initiated polyolcurative, wherein the amine initiated polyol curative contains at leastone nitrogen atom per molecule; wherein the amine initiated polyolcurative has an average of at least three hydroxyl groups per molecule;25 to 95 wt % of a high molecular weight polyol curative, wherein thehigh molecular weight polyol curative has a number average molecularweight, M_(N), of 2,500 to 100,000; and wherein the high molecularweight polyol curative has an average of 3 to 10 hydroxyl groups permolecule; and, 0 to 70 wt % of a difunctional curative; wherein thepolishing layer (20) exhibits a density of greater than 0.6 g/cm³; aShore D hardness of 5 to 40; an elongation to break of 100 to 450%; and,a cut rate of 25 to 150 μm/hr.

Preferably, the method for manufacturing a chemical mechanical polishingpad (10) of the present invention, further comprises: providing apressure sensitive platen adhesive (70); providing a release liner (75);applying the pressure sensitive platen adhesive (70) to the bottomsurface (27) of the rigid layer (25); and, applying the release liner(75) over the pressure sensitive platen adhesive (70), wherein thepressure sensitive platen adhesive (70) is interposed between the bottomsurface (27) of the rigid layer (25) and the release liner (75).

Preferably, the method for manufacturing a chemical mechanical polishingpad (10) of the present invention, comprises: providing a polishinglayer (20) with a counterbore opening (40) that opens on the polishingsurface (14), enlarges the through opening (35) and forms a ledge (45)(preferably, wherein the ledge (45) is parallel to the polishing surface(14)); wherein the counterbore opening has an average depth, D_(O-avg),from a plane (28) of the polishing surface (20) to the ledge (45)measured in a direction parallel to the central axis (12); wherein theaverage depth, D_(O-avg), is less than the average thickness of thepolishing layer, T_(P-avg); disposing the plug in place endpointdetection window block (30) within the counterbore opening (40) andbonding the plug in place endpoint detection window block (30) to thepolishing layer (20).

Preferably, the through opening (35) in the chemical mechanicalpolishing pad (10) is formed using at least one of a laser, a mechanicalcutting tool (e.g., a drill, a milling bit, a cutting die) and a plasma.More preferably, the through opening (35) is formed using a cutting die.Most preferably, the through opening (35) is formed by placing a mask,defining the cross section of the through opening (35) parallel to thepolishing surface (14), over the polishing layer (20) and using a plasmato form the through opening (35).

Preferably, the counterbore opening (40) is formed using at least one ofa laser, a mechanical cutting tool (e.g., a drill, a milling bit). Morepreferably, the counterbore opening (40) is formed using a laser. Mostpreferably, the counterbore opening (40) is formed by placing a mask,defining the cross section of the counterbore opening parallel to thepolishing surface, over the polishing pad and using a plasma to form thecounterbore opening.

The counterbore opening (40) is preferably formed before, after orsimultaneously with the formation of the through opening (35).Preferably, the counterbore opening (40) and the through opening (35)are formed simultaneously. More preferably, the counterbore opening (40)is formed first followed by the formation of the through opening (35).

The pressure sensitive platen adhesive (70) can be applied to the bottomsurface (27) of the rigid layer (25) before or after the formation ofthe through opening (35).

Preferably, in the method for manufacturing a chemical mechanicalpolishing pad of the present invention, providing the polishing layer(20), comprises: providing a polyfunctional isocyanate; providing acurative package, comprising: (i) providing at least 5 wt % (preferably5 to 30 wt %; more preferably 5 to 25 wt %; most preferably 5 to 20 wt%) of an amine initiated polyol curative, wherein the amine initiatedpolyol curative contains at least one nitrogen atom per molecule(preferably, wherein the amine initiated polyol curative contains one tofour nitrogen atoms per molecule; more preferably, wherein the amineinitiated polyol curative contains two to four nitrogen atoms permolecule; most preferably, wherein the amine initiated polyol curativecontains two nitrogen atoms per molecule); wherein the amine initiatedpolyol curative has an average of at least three hydroxyl groups(preferably 3 to 6 hydroxyl groups; more preferably 3 to 5 hydroxylgroups; most preferably 4 hydroxyl groups) per molecule; (preferablywherein the amine initiated polyol curative has a number averagemolecular weight of ≦700; more preferably 150 to 650; still morepreferably 200 to 500; most preferably 250 to 300); (ii) providing 25 to95 wt % (preferably 35 to 90 wt %; more preferably 50 to 75 wt %; mostpreferably 60 to 75 wt %) of a high molecular weight polyol curative,wherein the high molecular weight polyol curative has a number averagemolecular weight, M_(N), of 2,500 to 100,000 (preferably 5,000 to50,000; more preferably 7,500 to 25,000; most preferably 10,000 to12,000); and wherein the high molecular weight polyol curative has anaverage of 3 to 10 hydroxyl groups (preferably 4 to 8 hydroxyl groups;more preferably 5 to 7; most preferably 6) per molecule; and, (iii)providing 0 to 70 wt % (preferably 5 to 60 wt %; more preferably 10 to50 wt %; still more preferably 10 to 30 wt %; most preferably 10 to 20wt %) of a difunctional curative; mixing the polyfunctional isocyanateand the curative package to form a combination; and, allowing thecombination to react forming a polishing layer (20).

Preferably, in the method for manufacturing a chemical mechanicalpolishing pad of the present invention, providing the polishing layer(20), optionally, further comprises: providing a mold; pouring thecombination into the mold; and, allowing the combination to react in themold to form a cured cake; wherein the polishing layer (20) is derivedfrom the cured cake. Preferably, the cured cake is skived to derivemultiple polishing layers (20) from a single cured cake. Optionally, themethod further comprises heating the cured cake to facilitate theskiving operation. Preferably, the cured cake is heated using infraredheating lamps during the skiving operation in which the cured cake isskived into a plurality of polishing layers (20).

Preferably, the method of the present invention for polishing asubstrate, comprises: providing a substrate selected from at least oneof a magnetic substrate, an optical substrate and a semiconductorsubstrate (preferably, a semiconductor substrate; more preferably, asemiconductor substrate, wherein the semiconductor substrate is asemiconductor wafer); providing a chemical mechanical polishing pad (10)of the present invention; providing a polishing medium at an interfacebetween the polishing surface (14) and the substrate; providing a lightsource; providing a light detector; providing a control system; and,creating dynamic contact at the interface between the polishing surface(14) and the substrate; wherein the light source directs light throughthe plug in place endpoint detection window block (30) incident on thesubstrate; wherein the light detector detects light reflected from thesubstrate; wherein the control system receives an input from the lightdetector and determines when a polishing endpoint is reached.

The method of polishing a substrate of the present invention,optionally, further comprises: periodically, conditioning of thepolishing surface (14) with an abrasive conditioner.

Some embodiments of the present invention will now be described indetail in the following Examples.

Comparative Examples A-B and Examples 1-19

Polishing layers were prepared according to the formulation detailsprovided in TABLE 3. Specifically, polyurethane cakes were prepared bythe controlled mixing of the isocyanate terminated urethane prepolymerat 51° C. (i.e., the Adiprene® LF667 available from for ComparativeExample A and Examples 1-9; and, the Adiprene® LFG963A for ComparativeExample B and Examples 10-19; both available from Chemtura Corporation)with the components of the curative package. The amine initiated polyolcurative (i.e., the Voranol® 800 available from The Dow ChemicalCompany) and the high molecular weight polyol curative (i.e., theVoralux® HF505 available from The Dow Chemical Company) were premixedbefore blending in the other raw materials. All of the raw materials,except for MBOCA, were maintained at a premixing temperature of 51° C.The MBOCA was maintained at a premixing temperature of 116° C. The ratioof the isocyanate terminated urethane prepolymer and the curativepackage was set such that the stoichiometry, as defined by the ratio ofactive hydrogen groups (i.e., the sum of the —OH groups and —NH₂ groups)in the curatives to the unreacted isocyanate (NCO) groups in theisocyanate terminated urethane prepolymer, was as noted in Table 3.

Porosity was introduced into the polishing layers by adding Expancel®microspheres to the isocyanate terminated urethane prepolymer prior tocombining with the curative package to achieve the desired porosity andpad density.

The isocyanate terminated urethane prepolymer with any incorporatedExpancel® microspheres and the curative package were mixed togetherusing a high shear mix head. After exiting the mix head, the combinationwas dispensed over a period of 5 minutes into a 86.4 cm (34 inch)diameter circular mold to give a total pour thickness of approximately10 cm (4 inches). The dispensed combination was allowed to gel for 15minutes before placing the mold in a curing oven. The mold was thencured in the curing oven using the following cycle: 30 minutes ramp fromambient temperature to a set point of 104° C., then hold for 15.5 hoursat 104° C., and then 2 hour ramp from 104° C. to 21° C.

The cured polyurethane cakes were then removed from the mold and skived(cut using a moving blade) at a temperature of 30 to 80° C. intoapproximately forty separate 2.0 mm (80 mil) thick sheets. Skiving wasinitiated from the top of each cake. Any incomplete sheets werediscarded.

Note that Adiprene® LF667 used in the Examples is a PTMEG basedisocyanate terminated urethane prepolymer comprising a 50/50 weightpercent blend of Adiprene® LF950A and Adiprene® LF600D available fromChemtura. Also note that Adiprene® LFG963A is a PPG based isocyanateterminated urethane prepolymer available from Chemtura.

TABLE 3 Isocyanate terminated Curative Package (wt %) Expancel ® Poreurethane Prepolymer Voranol ® Voralux ® Stoichiometry Pore FormerPorosity Ex # prepolymer (% NCO) MBOCA 800 HF 505 (Active H/NCO) Former(wt %) (vol %) A Adiprene ® LF667 6.7 100 0 0 0.85 551DE40d42 1.8 35 BAdiprene ® LFG963A 5.8 100 0 0 0.9 551DE40d42 1.3 23 1 Adiprene ® LF6676.7 0 25 75 0.97 920DE40d30 1.3 34 2 Adiprene ® LF667 6.7 67 8 25 0.97920DE40d30 1.3 34 3 Adiprene ® LF667 6.7 0 14 86 1.0 551DE40d42 1.4 29 4Adiprene ® LF667 6.7 14 12 74 1.0 551DE40d42 1.4 29 5 Adiprene ® LF6676.7 25 11 64 1.0 551DE40d42 1.4 28 6 Adiprene ® LF667 6.7 25 11 64 1.0551DE40d42 0.6 15 7 Adiprene ® LF667 6.7 40 9 51 1.0 551DE40d42 1.4 28 8Adiprene ® LF667 6.7 50 7 43 1.0 551DE40d42 1.6 32 9 Adiprene ® LF6676.7 50 7 43 1.0 551DE40d42 0.7 18 10  Adiprene ® LFG963A 5.8 14 12 741.0 551DE20d60 2.0 28 11  Adiprene ® LFG963A 5.8 33 10 57 1.0 551DE20d602.0 28 12  Adiprene ® LFG963A 5.8 14 12 74 1.0 551DE20d60 1.4 22 13 Adiprene ® LFG963A 5.8 33 10 57 1.0 551DE20d60 1.5 23 14  Adiprene ®LFG963A 5.8 41 8 51 1.0 551DE20d60 1.4 22 15  Adiprene ® LFG963A 5.8 3310 57 1.0 — — — 16  Adiprene ® LFG963A 5.8 0 25 75 1.0 551DE20d60 2.0 2817  Adiprene ® LFG963A 5.8 0 14 86 1.0 551DE20d60 1.8 26 18  Adiprene ®LFG963A 5.8 25 19 56 1.0 551DE40d42 1.6 32 19  Adiprene ® LFG963A 5.8 2519 56 1.0 551DE40d42 0.7 17

The ungrooved, polishing layer materials from each of ComparativeExamples A-B and Examples 1-19 were analyzed to determine their physicalproperties as reported in TABLE 4. Note that the density data reportedwere determined according to ASTM D1622; the Shore D hardness datareported were determined according to ASTM D2240; the Shore A hardnessdata reported were determined according to ASTM D2240; and, theelongation to break data reported were determined according to ASTMD412.

The cut rate data reported in TABLE 4 were measured using a 200 mmMirra® polishing tool from Applied Materials. This polishing tool isdesigned to accommodate a circular chemical mechanical polishing padhaving a nominal diameter of 51 cm (20 inches). Polishing layers havinga circular cross section were prepared as described herein in theExamples. These polishing layers were then machine grooved to provide agroove pattern in the polishing surface comprising a plurality ofconcentric circular grooves having dimensions of 120 mil (3.05 mm)pitch, 20 mil (0.51 mm) width and 30 mil (0.76 mm) depth. The polishinglayers were then laminated to a foam sub-pad layer (SP2310 availablefrom Rohm and Haas Electronic Materials CMP Inc.)

A diamond conditioning disk (DiaGrid® AD3CL-150840-3 pad conditionermanufactured by Kinik Company) was used to abrade the polishing surfaceof the grooved polishing layers using the following process conditions:the polishing surface of the polishing layers were subjected tocontinuous abrasion from the diamond conditioning disk for a period of 2hours, with a platen speed of 100 rpm, a deionized water flow rate of150 cm³/min and a conditioning disk down force of 48.3 kPa (7 psi). Thecut rate was determined by measuring the change in the average groovedepth over time. The groove depth was measured (in μm/hour) using an MTIInstruments Microtrack II Laser Triangulation Sensor mounted on a ZaberTechnologies Motorized Slide to profile the polishing surface of eachpolishing layer from the center to the outer edge. The sweep speed ofthe sensor on the slide was 0.732 mm/s and the sampling rate(measurements/mm of sweep) for the sensor was 6.34 points/mm. The cutrate reported in TABLE 4 is the arithmetic average reduction in groovedepth over time, based on the collected thickness measurements takenas >2,000 points across the polishing surface of the polishing layer.

TABLE 4 Shore G′ @ G′ @ G″ @ G′@30° C./ Tensile Elongation Tensile CutDensity Hardness 30° C. 40° C. 40° C. G′@90° C. strength to breakmodulus Toughness rate Ex. # (g/cm³) A D (MPa) (MPa) (MPa) (MPa) (MPa)(%) (MPa) (MPa) (μm/hr) A 0.78 93 43 — 44.0 2.6 1.4 17 191 65 24 34 B0.88 91 41 — 49.0 3.2 1.9 15 293 95 62 26 1 0.76 56 10 3.2 3.1 0.1 1.0 3161 4 3 — 2 0.76 83 35 27.8 24.2 2.7 1.4 16 250 46 23 — 3 0.81 48 7 2.22.2 0.1 1.1 2 160 3 2 72 4 0.81 57 11 4.6 3.8 0.5 1.5 5 294 5 9 41 50.82 62 18 9.0 8.2 0.9 1.3 7 360 13 15 — 6 0.98 61 17 5.0 4.6 0.5 1.1 8414 7 16 — 7 0.82 75 23 16.8 15.6 1.4 1.3 11 346 26 22 30 8 0.79 79 2721.4 19.7 1.6 1.4 12 332 36 26 29 9 0.95 83 31 23.2 21.5 1.9 1.2 16 35140 34 — 10  0.83 56 10 6.0 4.5 0.9 2.8 4 189 6 5 46 11  0.82 75 23 18.613.4 3.0 6.0 7 256 31 13 — 12  0.90 61 14 8.2 6.4 1.2 3.1 4 164 8 4 —13  0.88 72 21 18.1 13.8 3.1 5.1 7 288 24 15 — 14  0.89 77 25 23.6 18.73.8 5.2 9 291 33 18 43 15  1.14 78 27 21.2 15.6 3.7 4.7 10 293 23 18 —16  0.83 55 10 5.6 4.5 0.7 2.0 3 162 4 3 — 17  0.85 57 11 4.6 4.0 0.41.7 3 143 4 2 — 18  0.78 70 19 18.0 13.3 2.6 4.7 5 173 23 7 — 19  0.9673 20 17.9 12.5 2.9 5.4 7 232 23 11 —

We claim:
 1. A chemical mechanical polishing pad, comprising: a polishing layer having a polishing surface and a base surface, a counterbore opening, a through opening, an average thickness, T_(P-avg), measured in a direction perpendicular to the polishing surface from the polishing surface to the base surface; a plug in place endpoint detection window block having an average thickness, T_(W-avg), along an axis perpendicular to a plane of the polishing surface; a rigid layer having a top surface and a bottom surface; a hot melt adhesive interposed between the base surface of the polishing layer and the top surface of the rigid layer; wherein the hot melt adhesive bonds the polishing layer to the rigid layer; optionally, a pressure sensitive platen adhesive; wherein the pressure sensitive platen adhesive is disposed on the bottom surface of the rigid layer; optionally, a release liner; wherein the pressure sensitive platen adhesive is interposed between the bottom surface of the rigid layer and the optional release liner; wherein the polishing layer comprises the reaction product of ingredients, comprising: a polyfunctional isocyanate; and, a curative package, comprising: at least 5 wt % of an amine initiated polyol curative, wherein the amine initiated polyol curative contains at least one nitrogen atom per molecule; wherein the amine initiated polyol curative has an average of at least three hydroxyl groups per molecule; 25 to 95 wt % of a high molecular weight polyol curative, wherein the high molecular weight polyol curative has a number average molecular weight, M_(N), of 2,500 to 100,000; and wherein the high molecular weight polyol curative has an average of 3 to 10 hydroxyl groups per molecule; and, 0 to 70 wt % of a difunctional curative; wherein the polishing layer exhibits a density of greater than 0.6 g/cm³; a Shore D hardness of 5 to 40; an elongation to break of 100 to 450%; and, a cut rate of 25 to 150 μm/hr; wherein the through opening extends through the polishing layer from the polishing surface to the base surface; wherein the counterbore opening opens on the polishing surface, enlarges the through opening and forms a ledge; wherein the counterbore opening has an average depth, D_(O-avg), from a plane of the polishing surface to the ledge measured in a direction perpendicular to the plane of the polishing surface; wherein the average depth, D_(O-avg), is less than the average thickness, T_(P-avg); wherein the plug in place endpoint detection window block is disposed within the counterbore opening; and, wherein the plug in place endpoint detection window block is bonded to the polishing layer.
 2. The chemical mechanical polishing pad of claim 1, wherein the top surface of the rigid layer is ungrooved; and wherein the bottom surface of the rigid layer is ungrooved.
 3. The chemical mechanical polishing pad of claim 1, wherein the top surface and the bottom surface of the rigid layer have a roughness, Ra, of 1 to 500 nm.
 4. The chemical mechanical polishing pad of claim 1, wherein the rigid layer is made of a biaxially oriented polyethylene terephthalate; wherein the rigid layer has an average thickness of 6 to 10 mils; and, wherein the rigid layer exhibits a Young's Modulus of 3,000 to 7,000 MPa.
 5. The chemical mechanical polishing pad of claim 1, wherein the polyfunctional isocyanate is an isocyanate-terminated urethane prepolymer having 2 to 12 wt % unreacted NCO groups; and, wherein the curative package, consists of: 5 to 20 wt % of the amine initiated polyol curative, wherein the amine initiated polyol curative contains two nitrogen atom per molecule; wherein the amine initiated polyol curative has an average of 4 hydroxyl groups per molecule; and, wherein the amine initiated polyol curative has a number average molecular weight, M_(N), of 200 to 400; 50 to 75 wt % of the high molecular weight polyol curative, wherein the high molecular weight polyol curative has a number average molecular weight, M_(N), of 10,000 to 12,000; and, wherein the high molecular weight polyol curative has an average of 6 hydroxyl groups per molecule; 10 to 30 wt % of the difunctional curative; wherein the difunctional curative is a diamine curative selected from the group consisting of 4,4′-methylene-bis-(2-chloroaniline) (MBOCA); 4,4′-methylene-bis-(3-chloro-2,6-diethylaniline) (MCDEA); and, isomers thereof; wherein the stoichiometric ratio of the reactive hydrogen groups in the curative package to the unreacted isocyanate groups in the polyfunctional isocyanate is 0.95 to 1.05; wherein the polishing layer exhibits a density of 0.75 to 1.0 g/cm³; a Shore D hardness of 5 to 20; an elongation to break of 150 and 300%; and, a cut rate of 30 to 60 μm/hr.
 6. The chemical mechanical polishing pad of claim 5, wherein the isocyanate-terminated urethane prepolymer has 5 to 7 wt % unreacted NCO groups; and, wherein the isocyanate-terminated urethane prepolymer exhibits a number average molecular weight, M_(N), of 400 to 2,500.
 7. The chemical mechanical polishing pad of claim 1, wherein the chemical mechanical polishing pad consists of: the polishing layer, the plug in place endpoint detection window block, the rigid layer, the hot melt adhesive interposed between the polishing layer and the rigid layer, the pressure sensitive platen adhesive disposed on the bottom surface of the rigid layer and the release liner; wherein the polyfunctional isocyanate is an isocyanate-terminated urethane prepolymer having 2 to 12 wt % unreacted NCO groups; and, wherein the curative package, consists of: 5 to 20 wt % of the amine initiated polyol curative, wherein the amine initiated polyol curative contains two nitrogen atom per molecule; wherein the amine initiated polyol curative has an average of 4 hydroxyl groups per molecule; and, wherein the amine initiated polyol curative has a number average molecular weight, M_(N), of 200 to 400; 50 to 75 wt % of the high molecular weight polyol curative, wherein the high molecular weight polyol curative has a number average molecular weight, M_(N), of 10,000 to 12,000; and, wherein the high molecular weight polyol curative has an average of 6 hydroxyl groups per molecule; 10 to 30 wt % of the difunctional curative; wherein the difunctional curative is a diamine curative selected from the group consisting of 4,4′-methylene-bis-(2-chloroaniline) (MBOCA); 4,4′-methylene-bis-(3-chloro-2,6-diethylaniline) (MCDEA); and, isomers thereof; wherein the stoichiometric ratio of the reactive hydrogen groups in the curative package to the unreacted isocyanate groups in the polyfunctional isocyanate is 0.95 to 1.05; wherein the polishing layer exhibits a density of 0.75 to 1.0 g/cm³; a Shore D hardness of 5 to 20; an elongation to break of 150 and 300%; and, a cut rate of 30 to 60 μm/hr.
 8. The chemical mechanical polishing pad of claim 7, wherein the isocyanate-terminated urethane prepolymer has 5 to 7 wt % unreacted NCO groups; and, wherein the isocyanate-terminated urethane prepolymer exhibits a number average molecular weight, M_(N), of 400 to 2,500.
 9. A method for manufacturing a chemical mechanical polishing pad, comprising: providing a polishing layer having a polishing surface, a base surface and an average thickness, T_(P-avg), measured in a direction perpendicular to the polishing surface from the polishing surface to the base surface; providing a plug in place endpoint detection window block having an average thickness, T_(W-avg), along an axis perpendicular to a plane of the polishing surface; providing a rigid layer having a top surface and a bottom surface; providing a hot melt adhesive in an uncured state; providing a through opening that extends through the polishing layer from the polishing surface to the base surface; providing a counterbore opening that opens on the polishing surface, enlarges the through opening and forms a ledge; wherein the counterbore opening has an average depth, D_(O-avg), from a plane of the polishing surface to the ledge measured in a direction perpendicular to the polishing surface; wherein the average depth, D_(O-avg), is less than the average thickness, T_(P-avg); interposing the hot melt adhesive in its uncured state between the base surface of the polishing layer and the top surface of the rigid layer; curing the hot melt adhesive, bonding the polishing layer and the rigid layer together; and, disposing the plug in place endpoint detection window block within the counterbore opening and bonding the plug in place endpoint detection window block to the polishing layer; wherein the polishing layer comprises the reaction product of ingredients, comprising: a polyfunctional isocyanate; and, a curative package, comprising: at least 5 wt % of an amine initiated polyol curative, wherein the amine initiated polyol curative contains at least one nitrogen atom per molecule; wherein the amine initiated polyol curative has an average of at least three hydroxyl groups per molecule; 25 to 95 wt % of a high molecular weight polyol curative, wherein the high molecular weight polyol curative has a number average molecular weight, M_(N), of 2,500 to 100,000; and wherein the high molecular weight polyol curative has an average of 3 to 10 hydroxyl groups per molecule; and, 0 to 70 wt % of a difunctional curative; wherein the polishing layer exhibits a density of greater than 0.6 g/cm³; a Shore D hardness of 5 to 40; an elongation to break of 100 to 450%; and, a cut rate of 25 to 150 μm/hr.
 10. The method of claim 9, further comprising: providing a pressure sensitive platen adhesive; providing a release liner; applying the pressure sensitive platen adhesive to the bottom surface of the rigid layer; and, applying the release liner over the pressure sensitive platen adhesive, wherein the pressure sensitive platen adhesive is interposed between the bottom surface of the rigid layer and the release liner. 